Baby Girl Found On Beach 'Sacrificed

A baby girl found on a Queensland beach actually died across the border in NSW, police say.

Police divers were conducting searches at Tweed Heads on Tuesday, after the nine-month-old's body was found on the beach at Surfers Paradise early on Monday

It's understood post-mortem results show the little girl drowned and may have been placed in the water at Tweed Heads, with her body eventually washing up 30 kilometres north at Surfers Paradise.

The baby's 47-year-old father is being extradited from Queensland by NSW Police on Wednesday. He will be charged on his return to NSW.

But it's believed the girl's mother, 23, will not face charges.

A police helicopter was seen combing the beach. Photo: 10 News First.

Police sources in Queensland allege the mother admitted to knowing about the planned "sacrifice" -- as it has been described to AAP -- but only the father would be accused of throwing her into the water.

Police sources have also said the mother has been released from custody and it's understood she has been placed in the mental health system in Queensland.

Queensland police detectives have been "deeply distressed" by the circumstance of the child's death, the sources said.

It comes as another baby girl, a four-month-old, died in a Brisbane hospital, with her death deemed suspicious.

The baby died in the Queensland Children's Hospital on Tuesday afternoon after being admitted to Logan Hospital on Monday morning with life-threatening injuries.

A woman, 35, and a man, 37, are assisting police with their inquiries, with detectives from the Logan Child Protection and Investigation Unit as well as homicide detectives investigating the baby's death.

Lead photo: 10 News First